LASC/LEE 2nd Edt; BHN PSI Discrepancy

[OnHoPr]

LASC Cast Boolit Notes states that an alloy of 12 BHN should have a minimum of 17.000 psi to create obturation. Lee 2nd Edition states on p. 134 that an alloy of 12 BHN should have no more than 15,536 max psi for his boolit strength philosophy. Could a few of the Boolit Masters please enlighten my thoughts on the discrepancy of the two philosophies?:confused::smile:

[mpmarty]

The higher figure which is supposed to assure "obturation" equates to deforming the boolit. Lees figures are based on 90% of ultimate tensile strength. Apples and tangerines as usual.

[462]

One formula used to determine the BHN/pressure relationship is PSI over 1400, in which case 17,000 psi divided by 1400 equals a BHN of 12.14. (When pressure is measured in CUP, divide by 1440.)

Absent any other information, I'd be more inclined to rely on Mr. Fryxell's figures than those of Mr. Lee.

[geargnasher]

LASC Cast Boolit Notes states that an alloy of 12 BHN should have a minimum of 17.000 psi to create obturation. Lee 2nd Edition states on p. 134 that an alloy of 12 BHN should have no more than 15,536 max psi for his boolit strength philosophy. Could a few of the Boolit Masters please enlighten my thoughts on the discrepancy of the two philosophies?:confused::smile:

Like MPMarty said, Lee's figures are based on 90% of the ultimate alloy strength.

A 12 BHN alloy may require 17K psi to "obturate" (totally wrong usage of the word, obturate means to seal, block, or obstruct, [as in "obturate the bore", where the boolit bumps up under pressure to deform and obturate the bore] the word here is "bump up" or deform due to exceeding the yield strength of the alloy), but the max psi Lee says to load that alloy to is only 15,536 psi, which is about 90% of 17,000. The first is the yield strength, the second is the margin for maximum loading pressure Lee recommends.

While Lee's theory and methods hold pretty much true in my testing, and it's a fine guideline for the average caster, it is NOT the Holy Writ, and many of us simply ignore it because it doesn't apply to advanced loading in many instances.

Gear

[cbrick]

Absent any other information, I'd be more inclined to rely on Mr. Fryxell's figures than those of Mr. Lee.

It's an honor to be associated with Glen Fryxell but there is nothing on the page in question from Glen except a couple of reviews such as the one for "Hollow Point Bullet Mold".
(http://www.lasc.us/CastBulletNotes.htm)

It is a collection of notes from my notebook and various publications.

Rick

[462]

Rick,
I didn't know that you are involved with the LASC web-page and are the source of that information, and did not mean to slight you. I figured -- wrongly -- that since Mr. Fryxell has written so many of the LASC articles, and "From Ingot to Target", that he was the source.

It seems the timeless adage about assuming is true.

I offer my apology.

[Glen]

I'd love to take credit for the Cast Bullets Notes information posted on the LASC site, but I'd be lyin' through my teeth! That impressive compilation of very useful data was put together by my friend Rick Kelter (webmaster of the LASC website).

[cbrick]

Not a problem, just didn't want Glen to see it without it being corrected.

The entire site is mine for better or worse. I publish everything of Glen's that I can get for obvious reasons.

Rick

[462]

Glen and Rick,
Thank you, gentlemen, for so willingly sharing your knowledge.

[OnHoPr]

From what I assume there are many ways to achieve a desired BHN. There is different alloy compositions, water quenching, heat treating and (?)etc. I may have not of read, recollect, or experienced everything. But in these many ways of achieving the desired BHN, does the desired BHN have different properties of obturation and ultimate tensile strength given the many ways to create the desired BHN?

[geargnasher]

Yes. That's why BHN should not be the primary consideration for loading. A 22 bhn straight linotype boolit and a 22 BHN OHT/WW boolit will have significantly different properties, though the same "hardness" number.

Many times, heat-treating produces a "better" boolit for the desired application than alloying to the same hardness and air-cooling them because the heat-treated boolit will be MUCH less brittle.

Gear

[cbrick]

You assume correctly OnHoPr, it can, if you harden an alloy by adding antimony (Sb) you end up with an increasing brittleness as the percentage of Sb goes up. As an example, casting with monotype (19% Sb) you can actually break a bullet in two by simply chambering a round. Linotype at 12% Sb does make a good bullet but is a poor choice on game or steel targets for it's brittleness.

If you have a 2 or 3% Sb alloy (WW) and quench or HT you can increase BHN without adding brittleness. Every alloy will have it's own BHN depending on the Sb, Sn in the alloy. Sb is the current method mostly used in both bullet casting and the metals industry to strengthen lead but it's a catch 22, to much of a good ain't a good thing.

Rick

[Bret4207]

From what I assume there are many ways to achieve a desired BHN. There is different alloy compositions, water quenching, heat treating and (?)etc. I may have not of read, recollect, or experienced everything. But in these many ways of achieving the desired BHN, does the desired BHN have different properties of obturation and ultimate tensile strength given the many ways to create the desired BHN?

You hit the point I was about to mention, Bhn means little without knowing the exact make up of the alloy and it's treatment. My advice is stop worrying about Bhn, fit your boolits, observe and record.

[ku4hx]

Even the very best researchers get slightly difference results when repeating the same experiment/test. Variables happen and differences occur. At least some of the difference is normal margin of error. The rest could be rounding up, rounding down and etc. I doubt very seriously if all the tests LASC did came out exactly on 17,000 ... just too many zeros there. In all likelihood, all published figures are some sort of average (weighted ot not) and are meant to be a guide at best.

There are natural variations in everything. That's why we have ways of analyzing data to express those variations: mean, mode, arithmetic average, standard deviation and ext. In fact, when examining numerical data of any sort you need to have those data sets too. Without them, data is pretty much meaningless.

Per the 2000 census, the average number of kids per family that had kids in the US was 1.86. Find me .86 of a kid. 1.86 is a mathematical construct that has no real meaning in real life.

www.census.gov/population/socdemo/hh-fam/tabST-F1-2000.pdf

[cbrick]

ku4hx, here is an cut & paste from this article on LASC: Heat Treating (http://www.lasc.us/HeatTreat.htm)

Excerpt from Cast Bullet Alloys and Obturation by Glen E. Fryxell: Extensive experimentation has revealed the empirical correlation of 3 x 480 x Brinell Hardness Number (BHN) (or more simply, 1440 x BHN) as an estimate of the minimum peak pressure required for bullet obturation (the reason for the "3 x 480" format is the number "4 x 480" also has significance, and this format makes it easier to remember both formulae). Thus, a bullet with a BHN of 24 (typical of commercial hard-cast bullets) will not undergo plastic deformation and obturate until pressures exceed 34,000 psi.

Excerpt from Heat Treat article: This formula is a guide to "minimum" pressure for a given load. It is not a set in concrete rule, it is a guide, a starting point. This formula WILL NOT tell you what the max pressure that will cause leading is as some believe, it is an approximation of a starting point. In a quality bore/chamber with a "properly sized" bullet it is very possible to run the pressure much higher than the formula suggests as a starting BHN without leading

Nothing about the formula was ever intended as a hard, set in concrete mathematical law. It is nothing more than one more thing to look at when deciding where to start. Bullet alloy can be and is varied by many means and every one of them can vary the performance of a given alloy when fired from a given firearm.

Rick

[runfiverun]

i'm pretty sure lee is also taking into consideration his tumble lube grooves.
those rely very,very heavily on fitment and pre-sealing of a bore the alox will not seal or repair any gas cutting.
it relies on size, and gas pressure to work.
his method works on a different principle than a traditional lube grooved boolit does.

[williamwaco]

LASC Cast Boolit Notes states that an alloy of 12 BHN should have a minimum of 17.000 psi to create obturation. Lee 2nd Edition states on p. 134 that an alloy of 12 BHN should have no more than 15,536 max psi for his boolit strength philosophy. Could a few of the Boolit Masters please enlighten my thoughts on the discrepancy of the two philosophies?



There is no real discrepancy here.

Lee recommends a 10% margin. LASC does not.

The Lee number of 15,536 is for BNH 12.1
His formula for BNH 12 produces 12*1422 = 17064. Reduce it by 10% and you get 15,357.

LASC states:
Example: Alloy BHN of 12 multiplied by 1422 = 17,064. An alloy of 12 BHN should be used with a load that develops a "minimum" of 17,000 psi.

Now a dose of reality:

The .44 magnum was developed with an alloy of 1/16 and 1/20 tin/lead. Elmer Keith's standard load was 22gr of 2400 with a 240 gr. bullet. My manuals indicate that load produces 35,000 psi. According to the formula, that pressure requires a BNH of 25. With Lee's 10% margin it would need 27.

Any one who has ever loaded the .44 magnum knows that BNH 25 is not required in the .44 magnum at 35,000 PSI.

The Keith alloy had a BNH of about 11.

I shot a zillion of those same loads cast with clip on wheel weights - BNH 15. Amazing accuracy and zero leading. Oh yes - those were plain base.

This gets me back to Waco's law No.1

"If it works, use it"

My favorite load in the .357 Magnum produces 37,000 psi according to Lyman. That means It needs to be cast of BNH 29 material.
Yikes. I use BNH 11-12 in that load. It produces 1500 fps, 1.5" 50 yard groups, and zero leading in my 12" Thompson Contender. And not only are those plain base bullets, they are also bevel base.

[303Guy]

Glen and Rick,
Thank you, gentlemen, for so willingly sharing your knowledge.I'll second that. Thanks guys!:drinks:

It puts meaning and understanding to some of my own observations (and corrects some of my misinterpretations and misobservations!)

There are other knowledgeable folks here too, all contributing to a great sight!:drinks:

[9.3X62AL]

Glen and Rick,
Thank you, gentlemen, for so willingly sharing your knowledge.

YES, INDEED! Thank you both.

There seems to be quite a bit of "cheat" in these formulae. 9mm and 40 S&W are other caliber examples where I routinely exceed the presumed pressure gradient limit with plain-based boolits, but good accuracy results with zero zilch nada bore leading. It works until it doesn't anymore.....then try a gas-check design.

[cajun shooter]

At 64 years of age I had the pleasure of reading articles every month written by Elmer and the joy of having two FTF chats. They were very short as they had several others trying to disrupt his morning beverage of choice.
I knew that he for the most part used bullets in the 20-1 alloy range. I decided a long time ago to stay with this alloy and have not been disapointed.

[44man]

Like MPMarty said, Lee's figures are based on 90% of the ultimate alloy strength.

A 12 BHN alloy may require 17K psi to "obturate" (totally wrong usage of the word, obturate means to seal, block, or obstruct, [as in "obturate the bore", where the boolit bumps up under pressure to deform and obturate the bore] the word here is "bump up" or deform due to exceeding the yield strength of the alloy), but the max psi Lee says to load that alloy to is only 15,536 psi, which is about 90% of 17,000. The first is the yield strength, the second is the margin for maximum loading pressure Lee recommends.

While Lee's theory and methods hold pretty much true in my testing, and it's a fine guideline for the average caster, it is NOT the Holy Writ, and many of us simply ignore it because it doesn't apply to advanced loading in many instances.

Gear
I have to agree here again because Gear knows. To "obturate" means "seal" and that should be done with "FIT", not "bump up."
When you need bump up for a small boolit, you also have lead too soft and the rest of the boolit will "slump."
I have years and years of experience with the musket and Minie' balls. Made small for BP fouling with a hollow base to expand and "obturate." Never, ever did they shoot right and a 6'X6' target at 50 yards was safe. I lapped molds for "FIT." and then the guns could hit a 200 meter gong.
NEVER will a boolit that needs to expand in a revolver shoot right.
I hate BHN numbers, they cover 1000 alloys.
You can shoot all kinds of alloys but none should need to expand.
What you need in a revolver, in fact, any gun is for the boolit to fit and be tough enough to engage the rifling without a skid too long. The base must be a perfect fit to the rifling to stop gas leakage.
Those pressure figures for "bump up" are wrong and should only be for "skid stop."
Soft lead might continue to expand after skid, but damage has been done. Like leak in a hose that you block with a finger. Water has already escaped.

[W.R.Buchanan]

This certainly was an enlightening read. Good to know some of "them that knows" are involved here, and keeping an eye out that our direction is strait and true!

Only buy the expansion of knowledge can any discipline advance...

Only by careful work of "them that knows" does it go in the right direction.

Success and Consistancy are the indicators used to decide who will be "Them that knows"

Randy

[OnHoPr]

I hope you will forgive my limited use of the English language and its vocabulary. Maybe I should have used comparison, debate or misunderstanding in the title of the OP. I feel like I'm in last semester of freshman year of CB101. Possibly, trying to absorb and comprehend enough data to ask a reasonable question. Your post have me pondering the grey (maybe silver area here) area of BHN and alloys. Maybe by the time I get to last semester of sophomore year of CB202 I'll be able ask more intelligent questions. Though, at any time during the learning process my questions will probably seem awkward. A couple of points attributed to my OP were.

A. In my particular rifle the softer alloys seem to be more accurate with higher pressures with slower powders (4064 to 4350). Furthermore, with the faster powders (4198 to 4895), I only start getting accuracy at the lower charges and harder alloys. With one exception, 19gr of 2400 with the RD alloy, A little over 1MOA.

B. I read about the slugging of barrels and the sizing of boolits. Take for example the .30 cal. If the bore diameter is .308 to .309 why size to .310 or .311 if you are getting obturation anyways? Won't the barrel only allow a given extrusion? Or are these different pressures of boolit bearing surface to the lands to enhance accuracy? :-?

[Idaho Sharpshooter]

cajun shooter,

I would have made the pilgrimage to the Shrine in Shreveport, to visit Bill Jordan. I first met him up at Mr Keith's home. Quite the pair. I had the rare opportunity to spend most of a day shooting Prairie Dogs with him up in Zortman, MT one summer.

Best Bill Jordan story: he was checked in the room next to us at the hotel. As my lovely wife and I are leaving the room for a get-together in the lounge. He actually remembered me, and said "hello." I introduced him to my wife, and we chatted a bit. I told Lorene about seeing him demonstrate fast draw by placing a silver dollar on the back of his hand, palm resting on the butt of his revolver. He would draw so fast that the dollar fell into his holster. He did demonstrations shooting wax bullets where he would hit a playing card at 10 feet or so.

He says, got a dollar? I say yes, and he goes back into his room. Comes back out with his Border Patrol pistol belt and holster on. He rests his hand on his M19 butt, palm down and sets my dollar on the back of his hand. Draws and dry fires the revolver as the silver dollar disappears in the holster. My wife says, can we see that again? He says yes, and asks me for another silver dollar. I give him one, and he repeats this amazing feat. This goes on for five more dollars, all the ones from the casino I had won earlier. He is casually pocketing the silver dollars in his vest pocket, one at a time.

I say something about the money on the way down the elevator, and he looks at me sideways out of one eye and says, most folks would be honored to get a fifteen minute private lesson in fast draw from Bill Jordan for just seven dollars. I just laughed, and he told my wife he would buy her a drink with the money. He and Elmer Keith were quite a pair to sit on a couch and just listen to their stories.

Rich

[W.R.Buchanan]

Idaho: You were very lucky to have had such an experience. I would have paid good money to talk to Keith or Jordan for 10 minutes. Most don't have the gumption to even talk to a "famous "person. When they finally do they find that famous people are just like everybody else, just more people know who they are.

I once spent 2 hours talking to Parnelli Jones and Walker Evans at a house party in Bullhead City AZ. When I got there I was completely drunk, 2 hours later they were drunk and I was sober and I knew everything there was to know about the Turbine Indy Car and Offroad Racing.. Parnelli gave me a ride in his Bronco the next afternoon and scared me senseless. This was in 1974. Walker still remembers that night. I have never ran into PJ again, but I will eventually.

These types of things shape our lives more than most know.

Randy

[OnHoPr]

What you need in a revolver, in fact, any gun is for the boolit to fit and be tough enough to engage the rifling without a skid too long. The base must be a perfect fit to the rifling to stop gas leakage.


Won't the barrel only allow a given extrusion? Or are these different pressures of boolit bearing surface to the lands to enhance accuracy?

Is these concepts close enough to consider the oversize boolit, like a .310 or .311 boolit for a .309 bore, in an eckstrusion fashion basically?

---------------
Back to the Lee and LASC content, neither of the two closely related concepts of BHN and pressure seemed to consider the time pressure wave from loading up a for ecksample a macks load of 4198 and a macks load of 4350. The gentler push. Another ecksample is LG's work with the 50/50 alloy in the 30-30 and a close to macks load of Leverevolution powder. That is a soft boolit and I am supposing the mid 30'sK in pressure with quite good accuracy. Now is this the ecksperience of boolit fit and/or the time pressure wave?

[44man]

Boy, there is so much good stuff here. Everyone here knows I do not believe in expanding a boolit to seal. Nor do I believe in a lube to seal. The boolit is the plug and as long as you don't deform it, it is good to go.
I would rather see the slump point and deformation as the key to the alloy and not BHN. Those numbers mean so little in the end.
I make an alloy that has shot PB to over 50,000 psi without deforming and with extreme accuracy that is a softer BHN then my normal WW metal.
It always is what you make your boolit do in your guns. I have shot some very soft stuff without leading and it was what I seen at the target that made me adjust. Most needed a GC but many still do not understand the GC function. You can ruin a boolit and fully lead a bore even with GC.

[Larry Gibson]

The problem with the LASC/Lee PSI to BHN theory is they are based on the structural failure point of pure lead. Our alloys (binary, ternary and those with Cu added) all have different and stronger structural strengths. The simplified formulas that LASC/Lee use assume a maximum psi/BHN point also do not consider bullet design and the rate of barrel twist. I have shot numerous ternary alloys upwards of 50K+ psi also w/o alloy failure whereas the LASC/Lee formulas tell me they should have failed in the 28 - 35K psi range.

Have to admit the formulas work pretty well with pure lead bullets though..........if that's the alloy you are using. If not then only testing with your alloy and loads in your gun with your components will give you the answer.

BTW; I also don't believe in bumping up, or obturating the bullet to seal the bore for best accuracy. Best accuracy will come in most standard milsurp and SAAMI spec chambers when the bullet fits the throat and is not more than .002 -.003 over groove diameter. The best accuracy will come if the throat and bullet drive band diameter are not over .001 of the groove diameter.

Larry Gibson

[OnHoPr]

Best accuracy will come in most standard milsurp and SAAMI spec chambers when the bullet fits the throat and is not more than .002 -.003 over groove diameter. The best accuracy will come if the throat and bullet drive band diameter are not over .001 of the groove diameter.

So, if my 94 seems to have a .308 bore and a .310 lead and I am sizing to a .309 boolit, this is where I may have had problems with the faster powders like 4198, Rel 7, Rel 10, AC 1680, AC 2015, AC 5744, and sort of AC 2460 with the softer alloy and a little less with the WQed alloy even if my boolit was touching the lands or if it was backed off a turn on the seating die? Then when I tried the slower powders like AC 4064, IMR 4350, and IMR 4007 ssc my groups shrank even with the softer hunting alloy. Was this an ecksample of the gentler push of the pressure time curve. With the faster powders in my scenario I may have been getting boolit distortion especially with the softer alloy from the jump into the barrel. So, if I honed a .309 sizing die just to where my boolit was the same dia. as my lead the faster powders would do better. Would this also help with the slower powders?

The only problem I had with these slower burning powders was that the barrel heated up fairly fast, like after the 4th shot, not good for the timed paper shoots. Though, the accuracy seemed very well for hunting. I had about a 1/4 lb of 2400 from back in the '70s for the .357 that I tried with the WQ scrap and surprisingly after 10 shots at a relative string pace the barrel seemed to be cooler than most of the other powders with about a 1.25" group. Does the new 2400 have the same characteristics?

For paper shoot testing I used WQ scrap and WWs. When I was checking for a hunting alloy I tried the Lyman #2, now I don't know if I alloyed it well or according to there specs, but from behind the target @ 100 yds in the sand berm there was little eckspansion and mostly nose shearing. So, I was checking out a RCBS catalog and noticed the/their silhouette alloy of 10 to 1 Pb/Sn, so I took that and micks it with the Lyman alloy 50/50 and used it for my hunting alloy. I know it mushrooms double at 270 yds with about 10 - 11" of penetration in a bocks of moist sand with not so much nose shearing @ the speeds the full loads of the slower powders were giving.

Sorry about so many questions in one post, but in my spin grab noodle when something seems to connect I will ask questions about it. Especially when there are so many successful styles of shooting boolits.